How long can you expose a scrubber to air?

[lermontov]

I would have thought absorbing moisture in a humid environment would be more of an issue - at least in a sealed box its more controlled

 

[broncobowsher]

Something else to consider is airflow. Just because a container isn't sealed, doesn't mean it gets a lot of airflow through it. A scrubber in a bag with the top folded over is almost sealed while a scrubber sitting on a bench with a fan flowing air over it will be completely different.

At one time I was on the hunt for the perfect sealed tupperware container. Now I have a drybag that is a good fit and just flop the top over if overnight or a couple folds if over a week.Close enough to sealed. I wonder how sealed the keg is anyway? I never get a pressure difference when opening them even after the weather/temperature/altitude changes.

 

[Dave Whitlow]

Yes. https://www.researchgate.net/profil...eather-carbon-dioxide-absorbent-canisters.pdf

Long words short :

So we see more than 22% reduced endurance time.

Personally i've prefer to use blind pugs for canister to seal it between dives.
And when filling - not to leave scrubber un-sealed for more time than needed to set it into canister and blind-plug it.

For repeat diving with the same lime I often leave the unit intact, with the loop closed.

For anything beyond next day I normally remove the lid, dry the cells, and seal the canister. I have AP Inspiration and use these

APD Scrubber Cover Kit with Large Bung for Side Tube (0019)

Scrubber cover that fits inspiration, evolution and vision

www.narkedat90.com

I've been doing this for the last 15 years and the scrubber monitor behaviour has been consistent with this being an effective strategy to preserve the lime.

 

[Agro]

The overnight ones seem to outperform the vaccum sealed ones (wider deviations, and the plots also kinda show it)

I think you are interpreting to much into this test.

Very small amount of test cycles, standard deviation.

 

[kensuf]

I would have thought absorbing moisture in a humid environment would be more of an issue - at least in a sealed box its more controlled

I would think the other way around would be the concern. Sorb has a fair amount of moisture in it straight from the jug, I believe typically around 20%. You don't want it to dry out by being exposed to conditioned air.

Carbon dioxide absorbents based on soda lime require specific amounts of moisture to be present to work efficiently. The amount of water incorporated into the different grades of material has been optimized for specific applications. Absorbent will not work if the water present in the material is frozen or the material has been allowed to dry out.

Source: Sofnolime Selection and Handling | Dive Gear Express®

Sofnolime® removes carbon dioxide (and other acidic
contaminants) from gas streams via an exothermic, water
facilitated, base catalysed chemical reaction. The Sofnolime®
contains a carefully controlled level of water which aids the
reaction.

Source: https://www.molecularproducts.com/wp-content/uploads/2017/01/Sofnolime-D-L-S-TDS-v9-1.pdf

 

[mr_v]

The topic frequently pops up in my group. I am surprised it is a concern. If you have a rebreather, do the following after each dive:

- Dry the canister. You can use moisture absorbers like Shamwow and fans to speed up the process.
- Put the scrubber back into the canister.
- Put the head/lid on the canister.

Problem solved.

 

[Agro]

The topic frequently pops up in my group. I am surprised it is a concern. If you have a rebreather, do the following after each dive:

- Dry the canister. You can use moisture absorbers like Shamwow and fans to speed up the process.
- Put the scrubber back into the canister.
- Put the head/lid on the canister.

Problem solved.

That's what the test proves.

 

[Vicko]

I wonder how sealed the keg is anyway? I never get a pressure difference when opening them even after the weather/temperature/altitude changes.

I use sofnolime 20kg canisters to keep gasoline, they seal well enough to swell up when left in the sunlight.

 

[Wibble]

The findings of that report are what one would "expect"; leave it out for 28 days and the scrubber looses its effectiveness.


My normal process is to remove the two scrubbers from the Revo and leave them to dry for a couple or few hours, then put them in a sealed Tupperware plastic container (one per scrubber). If the dive was more than 2 hours or deep, one scrubber would be emptied, refilled and sealed in the container if the unit isn't rebuilt.

 

[rddvet]

No offense but these questions about leaving scrubber packed and leaving in unit for how long are kind of dumb. It’s like asking how long will it take for my Hershey’s bar to melt in the sun. There’s so many variables there is no way to actually study it and get a universal answer that correlates to conditions outside of the study conditions.
Think about it. As soon as you open a tub of sorb it’s exposed to air. It’s not like sorb lives in some magical vessel that keeps it fresh. Sorb is constantly “degrading” if you think about it. Whether it’s in a dry unit, moist unit, or the tub.
Not sure why people keep bringing this topic up over and over